This proposal develops a nanostructured mimic of extracellular matrix prepared from a self-assembling peptide we call Multidomain Peptides or MDPs. The MDPs self-assemble into nanofibers that can be triggered to form a hydrogel. Because the peptides are easy to prepare and have a well defined design criteria many variations on the MDP architecture can be prepared which allow us to tailor 1) the conditions under which the fibers self-assemble (including conditions compatible with cell culture and in vivo applications), 2) the mechanical properties critical for handling and injectability, 3) the presentation of chemical information for cells, and 4) controlled biodegradation. This exceptional combination of properties will be developed here to create biomimetic scaffolds for the entrapment and delivery of cells, proteins and small molecule drugs. Our work will culminate with an in vivo application which uses this nanostructured hydrogel for dental regeneration. It is expected that the nanofibers will prove to be suitable as an injectable, localized, simultaneous delivery method for cells, proteins and small molecule drugs which will actively assist in directing cellular activity. Finally, after the MDP matrix has played its role it will degrade leaving behind only regenerated tissue. Such a matrix will play a critical role in future tissue engineering strategies (including, but not limited to, dental regeneration) which require a smart scaffolding material to organize the constituent cells and drugs until the body's own regenerative ability can take over. Our proposal is organized into four aims. Aim 1 will determine the design, flexibility and methods used to prepare MDP nanofibers. Aim 2 will optimize MDP nanofibers for three dimensional cell entrapment, cell delivery and cell mediated biodegradation. Aim 3 will develop a series of nanofibrous gels which will deliver growth factors and other small molecules localized in time and space. Aim 4 will test the above developed nanofibrous hydrogels ability to promote dental regeneration in vivo. This highly translational research will apply novel tissue engineering and nanotechnology concepts to the design of multidomain peptide hydrogels intended as an all-purpose scaffold for the regeneration tissue (tested here on the regeneration of the dentin-pulp complex). By combining expertise in chemistry, materials sciences, nanotechnology, cell biology and clinical dentistry we will generate data that will provide the framework for further studies testing these hydrogels in human clinical trials.